I am planning a P2P collaborative editing software and I was planning on going with WOOT. The problem would have been that I would have had loads and loads of tombstones (atoms are characters...) so I searched more and found this PDF about the Logoot approach. Everything is clear to me apart from one thing: why does every site need a clock? I couldn't find anything in the document that mentions the purpose of this value.
Is there a situation which requires a clock to be solved without conflict?